My explanation was maybe not accurate. (english is not my mother tongue sorry)
Of course, I always use the pragma strict and warnings
I must admit that I did not know -c but fortunatly my syntax is correct :)

However your are right, I misunderstood something. let me just explain why, because I would not like that you keep in mind a wrong opinion.
With $structure->[$j] I got an error message Global symbol "$struture" requires explicit package name
I know what I mean. I have to declare a variable with "my". I did not understand why because I thougt that $structure->[$j] was declared with my @structure
exactly like when you declare @array, you don't need to declare $arrray for using $arrray[$i].
With @structure->[$j], I got a message explaning that it is deprecated but at the ends it was working.

ok so my code is

my @statement;
...
my @structure;
foreach (@statement) 
{
...

push @structure , [];
for (my $i=0;$i<= $#ex; $i++) {
 push @{ $structure->[$j]}, $ex[$i]; 
}
}
[download]

but for the moment I have still this error. I will be more rigourous before asking another question
thanks
edit: it works with $structure[$j]. There is sometimes some things which look like strange but I know that strange behaviour of perl come from the misunderstanding of the programmer :)